Retaining The Uuid; Reading Or Writing The Eca Information - IBM R50 Series Hardware Maintenance Manual

Retaining the UUID

The Universally Unique Identifier (UUID) is a 128-bit
number uniquely assigned to your computer at production
and stored in the EEPROM of your system board. The
algorithm that generates the number is designed to provide
unique IDs until the year A.D. 3400. No two computers in
the world have the same number.
When you replace the system board, you must set the
UUID on the new system board as follows:
1. Install the ThinkPad Hardware Maintenance Diskette
Version 1.71 or later, and restart the computer.
2. From the main menu, select 4. Assign UUID.
A new UUID is created and written. If a valid UUID
already exists, it is not overwritten.

Reading or writing the ECA information

Information on Engineering Change Announcements (ECA)
are stored in the EEPROM of the system board. The
electronic storage of this information simplifies the
procedure to check if the ECA has been previously applied
to a machine. The machine does not need to be
disassembled to check for the ECA application.
To check what ECAs have been previously applied to the
machine, use the ECA Information Read/Write function on
the ThinkPad Hardware Maintenance Diskette Version 1.71
or later.
1. Insert the ThinkPad Hardware Maintenance Diskette
Version 1.71 or later, and restart the computer.
2. From the main menu, select 6. Set ECA Information.
3. To read ECA information, select 2. Read ECA/rework
number from EEPROM and follow the instruction.
4. To read box build date, select 5. Read box build date
from EEPROM, and follow the instruction on the
screen.
After an ECA has been applied to the machine, the
EEPROM must be updated to reflect the ECA's
application. Use the ThinkPad Hardware Maintenance
Diskette Version 1.71 or later to update the EEPROM.
Note: Only the ECA number is stored in the EEPROM.
The machine type of the ECA is assumed be the
same as the machine type of the machine that had
the ECA applied to it.
1. Insert the ThinkPad Hardware Maintenance Diskette
Version 1.71 or later, and restart the computer.
2. From the main menu, select 6. Set ECA Information.
ThinkPad R50/R50p and R51 Series
FRU replacement notices
65